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Drivers: hv: kvp,vss: Fast propagation of userspace communication failure

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If we fail to send a message to userspace daemon with cn_netlink_send()
there is no need to wait for userspace to reply as it is not going to
happen. This happens when kvp or vss daemon is stopped after a successful
handshake. Report HV_E_FAIL immediately and cancel the timeout job so
host won't receive two failures.
Use pr_warn() for VSS and pr_debug() for KVP deliberately as VSS request
are rare and result in a failed backup. KVP requests are much more frequent
after a successful handshake so avoid flooding logs. It would be nice to
have an ability to de-negotiate with the host in case userspace daemon gets
disconnected so we won't receive new requests. But I'm not sure it is
possible.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Vitaly Kuznetsov 2014-11-06 18:21:25 +01:00 committed by Greg Kroah-Hartman
parent 649142074d
commit 8d9560ebcc
2 changed files with 15 additions and 2 deletions
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9
drivers/hv/hv_kvp.c
View File

@ -350,6 +350,7 @@ kvp_send_key(struct work_struct *dummy)
__u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool;
__u32 val32;
__u64 val64;
int rc;
msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg) , GFP_ATOMIC);
if (!msg)
@ -446,7 +447,13 @@ kvp_send_key(struct work_struct *dummy)
}
msg->len = sizeof(struct hv_kvp_msg);
cn_netlink_send(msg, 0, 0, GFP_ATOMIC);
rc = cn_netlink_send(msg, 0, 0, GFP_ATOMIC);
if (rc) {
pr_debug("KVP: failed to communicate to the daemon: %d\n", rc);
if (cancel_delayed_work_sync(&kvp_work))
kvp_respond_to_host(message, HV_E_FAIL);
}
kfree(msg);
return;

8
drivers/hv/hv_snapshot.c
View File

@ -96,6 +96,7 @@ vss_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
static void vss_send_op(struct work_struct *dummy)
{
int op = vss_transaction.msg->vss_hdr.operation;
int rc;
struct cn_msg *msg;
struct hv_vss_msg *vss_msg;
@ -111,7 +112,12 @@ static void vss_send_op(struct work_struct *dummy)
vss_msg->vss_hdr.operation = op;
msg->len = sizeof(struct hv_vss_msg);
cn_netlink_send(msg, 0, 0, GFP_ATOMIC);
rc = cn_netlink_send(msg, 0, 0, GFP_ATOMIC);
if (rc) {
pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
if (cancel_delayed_work_sync(&vss_timeout_work))
vss_respond_to_host(HV_E_FAIL);
}
kfree(msg);
return;